<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script type="text/javascript">
      let data = new FormData();
        data.set('user','albert');
        data.append('user','albert');
        //console.log(data.get('user'));
        console.log(data.getAll('user'));
      </script>
  </head>
  <body>
<input type="text" name="" value="">
<ul>

</ul>
<li></li>
  </body>
</html>
